Apparatus for the assessment of the condition of fruits and vegetables

ABSTRACT

Apparatus for assessing the condition of fruit or vegetables comprises a transducer ( 22 ) which is brought into contact with the surface of fruit or vegetable ( 12 ) in a tapping motion. The transducer ( 22 ), where it contacts the fruit or vegetable&#39;s surface is generally curved in shape to ensure accuracy of measurement over a relatively wide range of angles of impact with the fruit or vegetable ( 12 ). The transducer ( 22 ) can be delivered to and away from the fruit or vegetable surface by an air controlled bellows arrangement.

This invention relates to improvements in or relating to apparatus forthe assessment of the condition of fruit and vegetables.

In our co-pending published PCT Application No. WO 98/52037 there isdisclosed an assembly for measuring the condition of fruit andvegetables in which an expandable resilient bellows arrangement, havingan active or passive sensor mounted therein, can be expanded so as tobring the sensor into contact with, or adjacent to, an item of fruit orvegetables whereby the sensor can react to a property of the fruit orvegetable (e.g. ripeness or firmness) and produce a signal related tothat property. The bellows assembly can then be retracted away from thefruit or vegetable. Published PCT Application No. WO 98/40737 alsodiscloses a similar arrangement.

A problem with these arrangements is that, for consistent measurement,it is necessary to ensure that the sensor moves towards the item offruit or vegetable substantially perpendicularly. If the sensor moves atan angle to the fruit or vegetable then inaccurate results can beobtained.

It is an object of the present invention to provide an arrangement ofthe type disclosed in the earlier applications mentioned above in whichit is possible to obtain a more consistent measurement over a relativelylarger angular range of impact between the sensor and the surface of thefruit or vegetable being tested.

Thus and in accordance with the present invention therefore there isprovided apparatus for measuring the condition of fruit and vegetablescomprising plunger means moveable into and out of contact with a surfaceof an item of fruit or vegetable, said plunger means carrying atransducer which is brought into contact with an item of fruit orvegetable, the transducer reacting to a property of said fruit orvegetable to produce an output signal related to that propertycharacterised in that at least a part of said plunger means ortransducer which contacts said item of fruit or vegetable is ofgenerally curved shape.

With this arrangement, the curved shape of the plunger or transducerensures a consistently accurate output signal related to the conditionof the fruit or vegetable over a relatively wide range of angles ofimpact of the plunger or transducer on the surface of the fruit orvegetable.

Preferably said plunger means is mounted in a resilient bellowsassembly, for movement therewith, the bellows assembly being capable ofexpansion under the action of pressurised air and retraction by theapplication of a vacuum. Alternatively any other form of means can beused as desired or appropriate to move the plunger or transducer intoand out of contact with an item of fruit or vegetable.

Most preferably the transducer comprises an active transducer and may,in a preferred embodiment comprise a piezoelectric sensor. It will beappreciated that the transducer can take any appropriate form asdesired, which is capable of measuring the condition e.g. ripeness,firmness or otherwise of the item of fruit or vegetable with which it isbrought into contact.

Preferably the plunger means or transducer is generally hemispherical inshape at least at the part thereof which contacts the fruit or vegetablesurface.

The invention will now be described further by way of example only andwith reference to the accompanying drawings in which:

FIG. 1 shows a schematic representation of one embodiment, not to scale,of an assembly in accordance with the present invention; and

FIG. 2 shows a view, partly in section, of a preferred embodiment ofassembly in accordance with the present invention, the assembly beingmounted within a bellows arrangement.

FIG. 1 shows an assembly 10 which can be moved into and out of contactwith an external surface of the fruit or vegetable 12 to be assessed.

The assembly 10 comprises a housing consisting of two interconnectedparts 13, 14. Mounted within the housing is a moveable slug 17 which ismoveable within the housing against the bias of a biasing member 18,preferably in the form of a spring. The slug 17 has an internal bore 19through which extends an electrical connection, 21 into connection witha transducer, preferably formed by an active piezoelectric sensor 22, ofgenerally curved, preferably hemispherical, form mounted at one end ofthe slug 17. The slug 17 is connected to a damping member 23 whichextends through aligned apertures 19, 28 in the slug 17 and housing part13 respectively. Conveniently, the electrical connection 21 will extendalong side or within the damping member 23.

In use the assembly 10 is moved towards the surface of a fruit orvegetable 12 to be tested. As the assembly 10 contacts the surface ofthe fruit or vegetables 12, the momentum of the slug 17 causes the slug17 to move, against the bias of the biasing means 18, to bring thepiezoelectric sensor 22 into contact with a surface of the fruit orvegetable 12 being tested. It will be appreciated that by positioningthe assembly of the invention an appropriate distance from the fruit orvegetables 12 to be tested it is possible for the movement of the sensor22 after the assembly 10 has contacted the fruit or vegetable to be atapping type of movement to the surface of the fruit or vegetable 12being tested. It will be appreciated that such a tapping motion will notaffect the condition of the fruit or vegetable being tested.

Because the piezoelectric sensor 22 has a curved surface, it is notnecessary for the sensor 22 to contact with the surface of the fruit orvegetable being tested precisely perpendicularly to achieve accurateresults using the assembly of the invention. The curvature of the sensor22 means that good measurements can be achieved over a range of anglesof contact with randomly curved surfaces of the fruit or vegetable 12 tobe assessed. This means that it is not necessary for either the fruitbeing tested or the sensor assembly to be precisely aligned for thesystem to produce accurate results.

The piezoelectric sensor 22 generates a signal which is indicative ofthe condition of the fruit or vegetable 12. The signal from thepiezoelectric sensor 22 is passed via the electrical connection 21 tosuitable processing circuitry and possibly a display (not shown).

The assembly 10 is then retracted thereby moving the sensor 22 away fromthe fruit or vegetable 12. During this movement, once again movement ofthe slug 17 within the housing is biased by the biasing means 18.

Referring now to FIG. 2, there is shown an assembly of the type of FIG.1 mounted in one suitable form of arrangement for moving the assembly 10towards and away from the fruit or vegetable. Thus FIG. 2 shows anassembly 10 mounted within a bellows assembly of the type described inU.S. Pat. No. 4,217,164. The bellows assembly expands as pressurised airis introduced moving the assembly 10 towards, and into contact with, thesurface of the fruit or vegetable 12. The assembly can then be retractedby introduction of a vacuum into the bellows which retracts the assembly10 away from the surface of the fruit or vegetable 12 being tested.Further details of the bellows assembly, and its operation are describedin detail in the abovementioned US patent, the contents of which areincorporated herein by reference.

The assembly 10 is preferably located internally of the bellows assemblyand is mounted so as to be moveable therewith in any suitable manner.

It will be appreciated that the assembly of the invention makes it moresimple to obtain consistent results without the need for absoluteprecision in setting up the assembly. It will be appreciated that it isimportant that accurate testing can be undertaken to prevent fruit orvegetables being incorrectly identified as to their condition.

It is of course to be understood that the invention is not intended tobe restricted to the details of the above embodiments which aredescribed by way of example only.

Thus, for example, whilst in the embodiment described, a bellowsassembly is utilised to move the assembly towards and away from thefruit or vegetable's surface, it is to be appreciated that any othersuitable mechanism can be used, as desired or as appropriate.

1. Apparatus for measuring the condition of fruit and vegetablescomprising a plunger movable into and out of contact with a surface ofan item of fruit or vegetable, said plunger carrying a transducer at adistal end thereof which is brought into contact with an item of fruitor vegetables, the transducer reacting to a property of said fruit orvegetables to produce an output signal related to that property, whereinthe transducer which contacts said item of fruit or vegetables is curvedin shape.
 2. Apparatus according to claim 1 mounted in a resilientbellows assembly, said bellows assembly being capable of expansion underthe action of pressurized air to bring the transducer into contact witha fruit or vegetable surface for measurement, and retraction by theapplication of a vacuum to move the transducer away from the fruit orvegetable surface.
 3. Apparatus according to claim 2 wherein thetransducer comprises an active transducer.
 4. Apparatus according toclaim 3 wherein the transducer comprises a piezoelectric sensor. 5.Apparatus according to claim 4 wherein the transducer is generallyhemispherical in shape at least at the part thereof which contacts thefruit or vegetable surface.
 6. Apparatus according to claim 3 whereinthe transducer is generally hemispherical in shape at least at the partthereof which contacts the fruit or vegetable surface.
 7. Apparatusaccording to claim 2 wherein the transducer is generally hemisphericalin shape at least at the part thereof which contacts the fruit orvegetable surface.
 8. Apparatus according to claim 1 wherein thetransducer comprises an active transducer.
 9. Apparatus according toclaim 8 wherein the transducer comprises a piezoelectric sensor. 10.Apparatus according to claim 9 wherein the transducer is generallyhemispherical in shape at least at the part thereof which contacts thefruit or vegetable surface.
 11. Apparatus according to claim 8 whereinthe transducer is generally hemispherical in shape at least at the partthereof which contacts the fruit or vegetable surface.
 12. Apparatusaccording to claim 1 wherein the transducer is generally hemisphericalin shape at least at the part thereof which contacts the fruit orvegetable surface.
 13. Apparatus according to claim 1 wherein theplunger comprises a housing within which is mounted a slug which carriessaid transducer wherein said slug is movable in said housing against thebias of a biasing member.
 14. Apparatus according to claim 13 whereinthe biasing means comprises a spring.
 15. Apparatus according to claim14 wherein said transducer is electrically connected by an electricalconnection and said electrical connection is associated with or disposedwithin a damping member.
 16. Apparatus according to claim 13, whereinmovement of said slug in said housing is additionally damped by adamping member.
 17. Apparatus according to claim 16 wherein saidtransducer is electrically connected by an electrical connection andsaid electrical connection is associated with or disposed within saiddamping member.
 18. Apparatus according to claim 14, wherein movement ofsaid slug in said housing is additionally damped by a damping member.19. Apparatus according to claim 18 wherein said transducer iselectrically connected by an electrical connection and said electricalconnection is associated with or disposed within said damping member.20. Apparatus according to claim 13 wherein said transducer iselectrically connected by an electrical connection and said electricalconnection is associated with or disposed within a damping member.